JB750 Posted October 24, 2014 Share Posted October 24, 2014 Hi all. After several attempts at sorting my overheating Disco 9 (see http://forums.lr4x4.com/index.php?showtopic=90727&hl=overheating), I thought I had sorted it out. I eventually replaced the thermostat and water pump, bled in several different ways as advised on here and she seemed to be rock steady at just under 1/2 on the temp gauge. After a few shortish trips and around 150 miles, all seemed well. But last night after around 20 mins, the temp started to climb again . I stopped before she went too high, opened up the cap and there was much knocking and burbling, so I assumed low water and air in there again. I let it cool a little and put about almost a gallon of coolant back in and the temp seemed to stabilize at very slightly higher than normal. She got us home OK and when I popped the bonnet, I noticed that there seemed to be a fair bit of water around the front and side of the expansion bottle. It also seemed to be hissing around the seam so my guess is that the bottle is leaking under pressure. Has anyone had this happen before? I am now looking for another bottle and hoping this will get rid of the issue once and for all!! Any ideas/suggestions gratefully received. Gotta love Discos!! Quote Link to comment Share on other sites More sharing options...
Nigelw Posted October 24, 2014 Share Posted October 24, 2014 I do love Disco's It has been known for the joint between the two halfs to split and also for the rad caps to fail holding pressure too. Have you had a sniff test for exhaust gasses in the water? (sorry, being lazy and not read your other thead yet, might be back with a new answer later ). I assume a 300Tdi? can be a bugger to bleed properly!!! Quote Link to comment Share on other sites More sharing options...
JB750 Posted October 24, 2014 Author Share Posted October 24, 2014 I do love Disco's It has been known for the joint between the two halfs to split and also for the rad caps to fail holding pressure too. Have you had a sniff test for exhaust gasses in the water? (sorry, being lazy and not read your other thead yet, might be back with a new answer later ). I assume a 300Tdi? can be a bugger to bleed properly!!! Not smelled the exhaust, but I don't see any evidence of steam in the gases. Also no signs of water in the oil or any pressure in the rocker cover. I've just bought a new expansion bottle and cap so next thing to do is try that. I had another look around the old bottle and it looks like there is a fair bit of moisture around the base and the seam. BTW, it is 300TDi as you say Quote Link to comment Share on other sites More sharing options...
Maverik Posted October 24, 2014 Share Posted October 24, 2014 A split bottle would cause over-heating and fluid loss, problem with water leaks is they usually evaporate on a hot engine so not always easy to track down. Split expansions bottles are a common problem i'm afraid. Quote Link to comment Share on other sites More sharing options...
Boydie Posted October 24, 2014 Share Posted October 24, 2014 I've put this proceedure out before but happy to explain it again, to effectivly bleed your coolant system you will need a 1/2" npt PVC male thread to female fitting, use PVC pipe glue and glue a large funnel into it and screw this into the top vent above the thermostat housing. Park the Disco on LEVEL ground, remove the vent plug out of the radiator and fill the expansion bottle until coolant is freely flowing out the radiator vent, replace the plug and fit the pressure cap onto the expansion bottle, you would have noticed that the coolant level in the expansion bottle was at the correct 1/2 way level. Next pour coolant into the funnel, fill it to 1/2 way and run the engine - gently squeese the top and bottom hose to assist in removing all the remaining air, once the thermostat has opened any remaining air will vent out of the funnel and be replaced by coolant, once this has occured, turn off the engine, allow it to cool down and remove the funnel and replace the vent plug, job done and the system has been fully filled. Dont forget to wash down any trace of coolant on th engine with clean water, it stains !!!! Quote Link to comment Share on other sites More sharing options...
JB750 Posted October 26, 2014 Author Share Posted October 26, 2014 Thanks for the replies guys. I have replaced both expansion bottle and cap as there is definitely staining around the seam of the old bottle. I bled the system by filling the radiator through the top cap, replaced the cap then filled the thermostat housing until the expansion bottle was showing the correct level. I then ran the engine with the radiator cap off for a few minutes, cracked the thermostat housing cap open until water came out then nipped it back up again. Then I put the expansion bottle cap back on and went for a short drive. All this done with the heater on max heat. The temperature was rock steady at the norm (just under half way), and the water level looked OK. I left it for about 15 minutes, checked the water, and it had risen by about 1 1/2 inches. I checked it again when the engine was fully cold and the bottle was almost full! I assumed some sort of air lock causing the water to back up in the bottle, (the radiator was still full). I drained the water to the fill level, ran the engine with the cap off and cracked the thermostat housing cap again until water ran out then re-tightened. Ran up to temp and then a short drive, the heater was hot, the water in the bottle dropped by around 1/2" and the top and bottom hoses were hot. The radiator was mostly hot, but only warm at the offside end (I assumed this was because I only went for a short drive rather than a blockage in the radiator?) I could smell no trace of diesel etc. in the coolant nor any steam or smell of antifreeze in the exhaust. Anyhow, checked the water the following morning and it was back to the fill line, and no signs of any loss that I could see. I will have to keep an eye on it for now and hope that all is well Quote Link to comment Share on other sites More sharing options...
Maverik Posted October 26, 2014 Share Posted October 26, 2014 Going for a good giggly drive often gets any air loks out the system... usually takes a few drives for the water level to settle itself out... in my expereince. Quote Link to comment Share on other sites More sharing options...
Boydie Posted October 26, 2014 Share Posted October 26, 2014 Land Rover issued a bullitin some years ago on the correct proceedure to fill/bleed the 300TDi system, which is what I explained in my previous comment, it's the only sure way of filling the system with coolant and getting rid of the air locks. Quote Link to comment Share on other sites More sharing options...
JB750 Posted November 1, 2014 Author Share Posted November 1, 2014 Well, I thought I had sorted it out after replacing the expansion bottle and cap. After a couple of shortish runs, the temp was rock solid, and the level in the expansion bottle dropped by around 1/2" or so once the water was up to temp, and returned to the fill line when cool. But after a run of around 60 miles today, although the temp was solid, the heater worked fine once warm, but after I stopped for about 10 minutes, when I restarted, although the temp was showing just a little under 'norm', the heater was almost cold, but after around 3-4 minutes of driving the heater was hot again. Once I stopped, I checked the water level, but this time it was up by around 1"!?? So I am now even more confused than before Can I assume it still has an airlock and hence the varying level of coolant in the bottle and heater issue? I cannot see any signs of leaking around the system. I am going to get an adaptor and try the method Boydie has suggested and see if that does the job. Any ideas gratefully received. Quote Link to comment Share on other sites More sharing options...
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